Cover opening and closing mechanism and apparatus provided with the same

ABSTRACT

A cover opening and closing mechanism has a shaft portion for slidably engaging a guide groove section, so that a cover is switched between a closed state and an open state relative to a main body. The guide groove section is provided on the main body, and includes two arc-shaped grooves. The shaft portion is provided on the cover, and includes two shafts guided in the arc-shaped grooves. A forcing device is provided between the main body and the cover for urging the cover. When the cover switches from the closed state to the open state, one of the shafts slides toward one end of one of the arc-shaped grooves around the other shaft after the other shaft slides toward the other end of the other of the arc-shaped grooves around the one shaft.

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT

The present invention relates to a cover opening and closing mechanism and an apparatus provided with the same, in which a cover is rotated to open and close a corresponding part of a box-like main body.

In a rotating-type cover opening and closing mechanism, a cover is usually pivotally supported on a box-like main body with a shaft to rotate and to switch between opening and closing states. In this case, in a case of a single-shaft construction, a rotational track of the cover is limited, and it is necessary to provide a relatively large gap with respect to the main body, so that the cover is not obstructed in the process of rotation. FIGS. 12(a) and 12(b) are views showing a conventional device having a dual-shaft construction to alleviate such a problem.

FIG. 12(a) shows a closed state of a cover, and FIG. 12(b) shows an open state thereof. Reference numeral 60 denotes a box-like main body, and reference numeral 61 denotes a cover for opening and closing an operating surface 60 a of the main body 60. A cover opening and closing apparatus comprises: a first bearing part 62 with an arc-shaped bearing surface 62 a, and an arc-shaped guide groove (hole) 63 concentric with the bearing surface 62 a, provided respectively on the main body 60; a first shaft 64, and a second shaft 65 for engaging the guide groove 63 to slide freely therein, provided respectively on the cover 61; a spring 66 provided between the main body 60 and the cover 61 for urging the cover 61 toward an open direction; and locking means (latch device) 68 provided on the main body 60 for engaging a coupling projection 67 on the cover 61.

In the closed state, the cover 61 is held by the locking means 68 with the first shaft 64 in contact with the bearing surface 62 a of the first bearing part 62. When the lock is released, the cover 61 is rotated and switched in the open direction by a force of the spring 66. In this case, at the start of the opening operation, the first shaft 64 works as a rotating shaft, and the second shaft 65 slides from one end (lower end) of the guide groove 63 toward the other end (upper end). After reaching the other end of the guide groove 63, the second shaft 65 works as a rotating shaft of the cover 61 in the subsequent opening operation.

In the cover opening and closing apparatus described above, the cover 61 moves following a track when the cover 61 is rotated with the first shaft 64 as a fulcrum (track corresponding to the guide groove 63), and following a track when the cover 61 is rotated with the second shaft contacting the other end (upper end) of the guide groove 63 as a fulcrum. Accordingly, it is possible to set the rotational track of the cover more arbitrarily than the single-shaft construction. Also, there is an advantage that the gap S between the cover 61 and the main body 62 can be made smaller.

Patent Document 1: Japanese Patent Publication (Kokai) No. 06-53671

As described above, the conventional cover opening and closing apparatus has the forcing means such as the spring 66 for urging the cover 61 in the open direction, and the locking means 68 for locking the cover against the force of the forcing means. The forcing means has functions of improving operability by rotating and switching the cover 61 automatically or semi-automatically from the closed state to the open state, and of preventing rattling of the cover 61 in the open state. The locking means 68 holds the cover 61 against the force of the forcing means in the closed state. Such an apparatus still has problems from the following viewpoints.

(a) In the conventional apparatus, the forcing means urges the cover exclusively toward the open direction. Accordingly, it is necessary to provide the locking means for holding the cover against the force in the closed state. In the locking means, the coupling projection provided on an inside surface or back surface of the cover for engaging the lock mechanism on the main body. Accordingly, not only it becomes a factor of increasing cost, but it also becomes a factor of damaging an appearance and obstructing the operability of the main body device since the constituent members are exposed in the open state of the cover.

(b) In the conventional apparatus, it is convenient that the cover is rotated and switched from the closed state to the open state by the force of the forcing means. On the other hand, when switching from the open state to the closed state, it is necessary to rotate the cover with an operating force proportional to the force of the forcing means. In this case, if the force of the forcing means is set to be small, it is possible to open and close the cover with a small force. However, it is difficult to automatically rotate the cover toward the open direction. Conversely, if the force is set to be large, the cover can be automatically rotated toward the open direction. However, it is difficult to close the cover. In other words, because the conventional forcing means urges the cover toward in one direction, in addition to the aforementioned problems, the operability in opening and closing the cover is limited, and it is difficult to improve the operability and increase quality.

(c) In order to improve the opening and closing operations of the cover, a damper is used for damping in the conventional apparatus. However, in the case when the cover has the complex rotational track in the above-mentioned dual-shaft construction, even when a damper is used, it is difficult to apply the damping force in the entire process of opening and closing of the cover.

An object of the present invention is to provide a cover opening and closing apparatus with improved quality, a wide range of application, and reduced cost, by eliminating the problems described above with a comparative simple method.

Further objects and advantages of the invention will be apparent from the following description of the invention.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, a cover opening and closing mechanism has a shaft on a side of a cover engaging a guide groove on a side of a box-like main body to slide freely therein, so that the cover is rotated and switched accompanying sliding of the shaft between a closed state and an open state relative to a corresponding part of said main body. The guide groove is provided on the side of the main body, and comprises a first arc-shaped groove and a second arc-shaped groove with a distance in between. The shaft is provided on the side of the cover, and comprises a first shaft guided in the first arc-shaped groove and a second shaft guided in the second arc-shaped groove. With a force or resistance of forcing means provided between the main body and the cover, the cover switches from a closed state, where the first shaft is positioned at one end of the first arc-shaped groove and the second shaft is positioned at the other end of the second arc-shaped groove, to an open state, where the second shaft slides toward one end of the second arc-shaped groove with the first shaft as a fulcrum after the first shaft slides toward the other end of the first arc-shaped groove with the second shaft as a fulcrum. Also, the cover is urged and held in the closed state.

According to a second aspect of the invention, the above cover opening and closing mechanism is defined by an apparatus structure. A cover opening and closing apparatus has a guide groove provided on a side of a box-like main body and a shaft provided on a side of a cover for engaging the guide groove to slide freely therein, so that the cover is rotated and switched accompanying sliding of the shaft between a closed state and an open state relative to a corresponding part of the main body. An upright wall is provided on the side of the main body, and has a first arc-shaped groove and a second arc-shaped groove with a distance in between as a guide groove. An arm is provided on the side of the cover, and has a first shaft guided in the first arc-shaped groove and a second shaft guided in the second arc-shaped groove as a shaft. Forcing means is provided between the upright wall and the arm, so that the cover switches from a closed state, where the first shaft is positioned at one end of the first arc-shaped groove and the second shaft is positioned at the other end of the second arc-shaped groove, to an open state, where the second shaft slides toward one end of the second arc-shaped groove with the first shaft as a fulcrum after the first shaft slides toward the other end of the first arc-shaped groove with the second shaft as a fulcrum. Also, the cover is urged and held in the closed state.

In each of the aspects of the invention, the main body includes a housing, a case or the like, of a device, and the cover includes a door, a cover, or the like. Each shaft includes a protrusion, a pin, or the like, for engaging to slide freely in the corresponding first arc-shaped groove and second arc-shaped groove on the side of the main body.

The above cover opening and closing mechanism and apparatus have the following features different from those of a dual-shaft construction shown in FIGS. 12(a) and 12(b). The guide groove is formed of the two independent arc-shaped grooves. When the cover is switched from the closed state to the open state or from the open state to the closed state, one of the first shaft and the second shaft slides with the other as a fulcrum, or the other slides with the one as a fulcrum. The forcing means holds the cover to prevent rattling thereof in the open state and also in the closed state. The cover is rotated and switched between the closed state and the open state along the tracks of the first arc-shaped groove and the second arc-shaped groove, and is rotated against the force of the forcing means at the start of each switching operation. The cover opening and closing mechanism and apparatus may have the following structures as preferable aspects.

According to a third aspect of the invention, the arm is assembled together with the forcing means on the upright wall, and a damping means is provided between a frame and the arm for damping a rotational switching speed of the cover. In this aspect, for example, the upright wall on the side of the main body is constituted as a frame to be a unit product. The damping means is assembled together with the forcing means in advance, thereby improving handling ability and ability to assemble onto the main body.

According to a fourth aspect of the invention, the damping means comprises a damper attached on the arm and having a rotating gear, and plural teeth parts provided at different positions on the upright wall for engaging the rotating gear in a switching manner from one end to the other end when the cover is switched from the closed state to the open state. In this aspect, it is possible to apply a damping force to the cover in virtually the entire process of opening and closing with a simple construction of the teeth parts at the multiple positions in the dual-shaft construction.

According to a fifth aspect of the invention, the main body is provided with an escape groove on a side of a front bottom wall thereof for escaping the arm. Also, a cover member is pivotally supported on the upright wall to stand up for covering the escape groove from the front when the cover switches from the closed state to the open state. In this aspect, when the cover moves to the open state greatly backward following the bottom side of the corresponding part of the main body as in an embodiment, the simple cover member covers the escape groove to be invisible, so that an external appearance is not degraded due to the escape groove provided on the side of the main body for escaping the arm on the side of the cover.

The cover opening and closing mechanism and an apparatus of the present invention have the following advantages. In the first and second aspects, the cover is held in the closed state by the forcing means. Accordingly, it is possible to eliminate locking means for holding the cover in the closed state as in the conventional apparatus. As a result, it is possible to reduce cost corresponding to the locking means, simplify the assembly capability, and improve the external appearance characteristics. Also, in the cover opening and closing operation, the cover is operated against the force of the forcing means only in the initial stage, and afterwards the cover is rotated by the force, thereby maintain good operability. Also, the rotational track of the cover can be set within a wide range by changing the tracks of the first arc-shaped groove and the second arc-shaped groove.

In the third and fourth aspects, with the damping means, the cover is opened and closed at a substantially constant speed, thereby providing high quality. In this case, although the damping means is also provided in the conventional apparatus, in the invention, it is possible to apply the damping action virtually in the entire process of opening and closing of the cover even in the dual-shaft construction.

In the fifth aspect, even when the cover moves to the open state greatly toward the side of the bottom of the corresponding part of the main body, the cover member eliminates the factor degrading the external appearance, thereby maintaining the external appearance characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1(a) to 1(c) are schematic explanatory views showing an example of a device using a cover opening and closing apparatus of the invention, wherein FIG. 1(a) shows a closed state of a cover, FIG. 1(b) shows an open state of the cover, and FIG. 1(c) shows a schematic external view in the open state;

FIG. 2 is a structural view showing a relationship between a left-side apparatus of the invention and a main body on a side of the device shown in FIG. 1(a) to 1(c);

FIG. 3 is a structural view showing a relationship between a right-side apparatus of the invention and the main body on the side of the device shown in FIG. 1(a) to 1(c);

FIGS. 4(a) and 4(b) are views showing an operation of the apparatus in closed and open states of the left-side apparatus, wherein FIG. 4(a) shows the closed state of the cover, and FIG. 4(b) shows the open state of the cover;

FIGS. 5(a) and 5(b) are views showing an operation of the apparatus in which a cover shown in FIGS. 4(a) and 4(b) is switched from the closed state to the open state;

FIG. 6 is a drawing showing the operation of the right-side apparatus corresponding to FIG. 5(a);

FIG. 7 is a structural drawing showing a relationship between a frame and an arm of the left-side apparatus of the apparatus;

FIGS. 8(a) to 8(c) are structural views showing the frame of the left-side apparatus, wherein FIG. 8 (a) is a top view thereof, FIG. 8(b) is a side view thereof, and FIG. 8(c) is a sectional view taken along line 8(c)-8(c) in FIG. 8(b);

FIGS. 9(a) to 9(c) are structural views showing the arm of the left-side apparatus, wherein FIG. 9(a) is a top view thereof, FIG. 9(b) is a side view thereof, and FIG. 9(c) is a sectional view taken along line 9(c)-9(c) in FIG. 9(b);

FIGS. 10(a) to 10(c) are structural views showing the frame of the right-side apparatus, wherein FIG. 10(a) is a top view thereof, FIG. 10(b) is a side view thereof, and FIG. 10(c) is a sectional view taken along line 10(c)-10(c) in FIG. 10(b);

FIGS. 11(a) to 11(c) are structural views showing the arm of the right-side apparatus, wherein FIG. 11 (a) is a top view thereof, FIG. 11(b) is a side view thereof, and FIG. 11(c) is a sectional view taken along line 11(c)-11(c) in FIG. 11(b); and

FIGS. 12(a) and 12(b) are explanatory views showing a conventional example of a cover opening and closing apparatus, wherein FIG. 12(a) shows a closed state of a cover, and FIG. 12(b) shows an open state thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereunder, embodiments of the present invention will be explained with reference to the accompanying drawings. FIGS. 1(a) to 1(c) are views showing an example of a device using a cover opening and closing apparatus (hereunder referred to as an apparatus) of the present invention, wherein FIG. 1(a) shows the closed state of the cover, FIG. 1(b) shows the open state of the cover, and FIG. 1(c) shows a schematic external view in the open state. FIG. 2 is a structural drawing showing a relationship between a left-side apparatus and a main body shown in FIGS. 1(a) to (c), and FIG. 3 is a structural drawing showing a relationship between a right-side apparatus and the main body shown in FIGS. 1(a) to 1(c).

FIGS. 4(a) and 4(b) to 5(a) and 5(b) show an operation of the apparatus of the present invention in the left-side apparatus shown in FIG. 2, and FIG. 6 shows the operation of the right-side apparatus shown in FIG. 3. FIG. 7 is a structural drawing showing relationships among main members of the apparatus in the left-side apparatus. FIGS. 8(a) to 9(c) are unit drawings of a frame (upright wall) and an arm of the left-side apparatus, and FIGS. 10(a) to 11(c) are unit drawings of a frame (upright wall) and an arm of the right-side apparatus. In FIGS. 8(a) to 8(c), FIG. 8(a) is a top view thereof, FIG. 8(b) is a side view thereof, and FIG. 8(c) is a sectional view taken along line 8(c)-8(c) in FIG. 8(b). Similarly, in FIGS. 9(a) to 11(c), FIGS. 9(a), 10(a), and 11(a) are top views, FIGS. 9(a), 10(a), and 11(a) are side views, and FIGS. 9(c), 10(c), and 11(c) are sectional views taken along lines 9(c)-9(c), 10(c)-10(c), and 11(c)-11(c) in FIG. 9(b), 10(b), and 11(b), respectively. In the explanation below, a general outline is described, and then essential components of an embodiment will be described in detail.

(Outline) A device shown in FIGS. 1(a) to 1(c) is a liquid crystal projector, which has an opening 11 a on a front surface 11 of a main body 10, and a projection lens extends and retracts from the opening 11 a. Design features are as follow: for improving external appearance characteristics and convenience of use and the like, instead of a construction in which a cap is installed on and removed from the opening 11 a, a rotating-type cover 15 is provided. The cover 15 is capable of opening and closing the front surface 11 including the opening 11 a with an apparatus 1 of the invention.

As shown in FIGS. 1(a) to 3, the main body 10 is formed roughly in a rectangular box shape, and has a front surface 11, a back surface, two side surfaces 12, and upper and lower surfaces 13 and 14. The opening 11 a is provided on the front surface 11. On the left side surface 12, a heat discharge part 12 a formed of a large number of holes is provided. On the lower surface 14, plural leg members 14 a for height adjustment, an escape groove 14 b with an opened front bottom wall part, and attachment parts 14 c-14 e upright corresponding to the escape groove 14 b, and the like are provided. The escape groove 14 b and the attachment parts 14 c-14 e are provided on each of both sides. Each escape groove 14 b is formed across a front bottom wall part of the lower surface 14 from a lower side wall part of the front surface 11. Left and right apparatuses 1 of the invention are attached on the attachment parts 14 c-14 e on both sides.

The cover 15 is formed in a horizontally elongated rectangular plate shape corresponding to the front surface 11 of the main body. The cover 15 has a projection 15 a on an inside surface or the back surface for an attachment provided on both lower sides roughly corresponding to the escape grooves 14 b on both sides, and a recessed part 15 b provided on the inner surface side of the piece for placing a finger.

Each apparatus 1 is made so as to rotate and switch the cover 15 between a closed state and an open state (fully open state) relative to an opening or operating surface (front surface 11) of the main body 10, in a state in which two shafts of the cover 15 engage corresponding guide grooves on the main body 10 to slide freely therein. Structural features are as follows: a first arc-shaped groove 20 and a second arc-shaped groove 21 are provided on a frame 2 on the side of the main body 10 above and below with a distance in between as the guide groove; a first shaft 8 engaging the first arc-shaped groove 20 and a second shaft 9 engaging the second arc-shaped groove 21 are provided on an arm 3 on the side of the cover 15 as the shaft; and the cover 15 is subject to force or resistance of a spring member 5 provided between the frame 2 and the arm 15.

The apparatus is capable of switching from a closed state wherein the first shaft 8 is positioned at one end of the first arc-shaped groove 20 and the second shaft 9 is positioned at the other end of the second arc-shaped groove 21 to an open state wherein the second shaft 9 slides toward one end of the second arc-shaped groove 21 with the first shaft 8 as a fulcrum after the first shaft 8 slides toward the other end of the first arc-shaped groove 20 with the second shaft 9 as a fulcrum. The cover 15 also is forced and held in the closed state. When the apparatus 1 of the present invention is applied as a cover opening and closing mechanism, it is also possible that the frame 2 may be integrally formed as an upright wall on the main body 10, and the arm 3 may be integrally formed in an arm shape on the cover 15.

In the apparatus 1 of the embodiment, main members include a frame 2 fixed on the side of the main body 10; the arm 3 connected to the cover 15; a cover member 4 pivotally supported on the frame 2 and standing up or tilting down in association with a movement of the arm 3; a spring member 5 provided between the frame 2 and the arm 3; and a damper 6 for damping, and these are formed in a unit. As for a material, the frame 2, arm 3, and cover 4 are plastic molded products, and they also may be formed of other materials.

Also, the frame 2 and the arm 3 have different shapes between the left-side apparatus 1 (shown in FIGS. 2, 4(a) and 4(b), 5(a) and 5(b), 7, and 9(a) to 9(c)) disposed on the left side in FIG. 1(c) and the right-side apparatus 1 (shown in FIGS. 3, 6, 10(a) to 10(c), and 11(a) to 11(c)) disposed on the right side, and they are the same in terms of an operation. This is because, for example, the frame 2 and the arm 3 of the left-side apparatus 1 are made so as not to obstruct the passage of air from a radiation part 12 a on the side surface 12 of the main body. In the explanation below, it is discussed mainly with respect to the left-side apparatus 1.

As shown in FIG. 7 and FIGS. 8(a) to 8(c), the frame 2 has roughly a flat plate shape, and comprises: a first arc-shaped groove 20 and a second arc-shaped groove 21, as well as arc-shaped teeth parts 23 a and 23 b, which are provided on a main part; an attachment piece 24, a cover member restriction piece 25, and an attachment shaft 26, which are provided on the front side; attachment pieces 27 and 28 which are provided on the back two sides; and a spring member engaging part 29 provided on the back side wall part where the attachment piece 28 projects. Reference numerals 22 a to 22 c denote air ventilation holes penetrating from left to right in the main body. The ventilation holes 22 a to 22 c are omitted on the side of the right-side frame 2, and the corresponding parts are formed as recessed parts.

Conversely, although the right-side frame 2 has a projecting piece 22 d projecting outwardly on the side of the upper piece of the main part, the projecting piece 22 d is omitted on the side of the left-side frame 2. The attachment pieces 27 and 28 have attachment holes, positioning holes or the like, and are formed in shapes at places corresponding to the attachment parts 14 c to 14 e on the lower side 14 of the main body as mentioned above.

Here, the first arc-shaped groove 20 and the second arc-shaped groove 21 are positioned at an upper and a lower position, respectively, and extend in the forward-to-backward direction. When one ends 20 a and 21 a are located at the back sides of the grooves, and the other ends 20 b and 21 b are located at the front sides of the grooves (refer to FIGS. 8(a) to 9(c)), the other ends 20 b and 21 b of the respective grooves are separated from each other by a distance greater than a distance between the one ends 20 a and 21 a.

As for tracks, for example, the first arc-shaped groove 20 is formed in an arc shape around the other end 21 b of the second arc-shaped groove 21, and the second arc-shaped groove 21 is formed in an arc shape around the other end 20 b of the first arc-shaped groove 20.

Teeth parts 23 a and 23 b are located at an upper and a lower position, and provided from a front to a center in the forward-to-backward direction. The teeth part 23 a has an arc-shaped rib between a center of a rib along the first arc-shaped groove 20 and a front side of the main part, and a fixed number of teeth are formed continuously on the rib. The teeth part 23 b has an arc-shaped rib a center of a rib along the second arc-shaped groove 21 and the front side of the main part, and a fixed number of teeth are formed continuously on the rib.

The teeth parts 23 a and 23 b correspond to teeth parts 23 c and 23 d formed on the side of the right-side frame 2 (refer to FIGS. 10(a) to 10(c)). That is, the teeth parts 23 a and 23 b and the teeth parts 23 c and 23 d are provided on roughly the same arc-shaped ribs of the left and right frames 2. The upper-side teeth parts 23 a and 23 c have the numbers of teeth different from those of the lower-side teeth parts 23 b and 23 d. In this example, the number of teeth on the upper-side teeth part 23 a is greater than that of the corresponding teeth part 23 c, and the number of teeth on the lower-side teeth part 23 b is smaller than that of the corresponding teeth part 23 d. With this structure, a rotating gear 7 of the damper 6 (described later) formed on the side of the arm 3 can engage the teeth of one of the teeth parts 23 a to 23 d in the entire process of rotating and switching the cover 15 between the closed and open states.

On the frame 2, the cover member 4 is assembled onto an attachment shaft 26 on the front side. As shown in FIGS. 2, 3, and 4(b), the cover member 4 is integrally formed of a plate piece-shaped support part 40; a cover part 41 provided on the side of the front piece of the support part 40; a small stopper piece 42 projecting outwardly on the side of the front piece of the support part 40 adjacent to the cover part 41; and a boss part 43 projecting outwardly on the side of the base piece of the support part 40.

The cover member 4 is assembled onto the frame 2 with the boss part 43 fitted in the attachment shaft 26 to be rotatable and held not to come off. At that time, a coil spring 17 is incorporated in a state being held on an outer perimeter of the boss part 43. That is, the coil spring 17 has a spring-wound part at a center part thereof, and one end is fixed on a vertical rib on the side of the frame 2 and the other end is fixed over a corresponding part of the support part 40 in a state that the spring-wound part is held on the boss part 43.

On the other hand, as shown in FIGS. 7, 9(a) to 9(c), and 11(a) to 11(c), the arm 3 has roughly a flat plate shape, and is formed of a large plate width part 30 overlaid on the main part of the frame 2 and a connecting part 31 projecting outwardly on the front side of the part 30. The part 30 has a placement hole 33 penetrating from left to right at a center part thereof; engaging parts 34 as cut out places of the placement hole 33 in the diameter direction; an upper-side boss part 35 for holding the first shaft 8 engaging the first arc-shaped groove 20; a lower-side boss part 36 for holding the second shaft 9 engaging the second arc-shaped groove 35; and a engaging part 37 projecting outwardly to the side of the upper piece.

The inside of the cylinder of each boss part 35 and 36 is formed as a small-diameter attachment hole 35 a and 36 a. Reference numerals 32 a to 32 c denote air ventilation holes penetrating from left to right in the part 30. The ventilation holes 32 a to 32 c are omitted on the side of the right-side arm 3, and corresponding parts are formed as recessed parts. The connecting part 31 has an insertion hole 31 a recessed toward the part 30 from the front end surface, and an attachment hole 31 b penetrating in the insertion hole 31 a from the lower surface.

A damper 6 is installed in the placement hole 33 and the engaging parts 34. The damper 6 is a well-known hydraulic type having a rotating gear 7 and, for example, is constituted such that the rotating gear 7 rotates under the resistance of operating oil inside a main body. In this example, the damper 6 has two elastic checking pieces attached on the perimeter of the main body. Also, the damper 6 is installed on the arm 3 by aligning each of the elastic checking pieces to the corresponding engaging parts 34 and pushing into the placement hole 33 from that state. In the installed state, the main body of the damper 6 is positioned inside the placement hole 33, and the rotating gear 7 projects outwardly from the corresponding side surface of the arm 3.

The arm 3 with the damper 6 is placed on the frame 2 as shown in FIG. 7, and is assembled thereon through the first shaft 8 and the second shaft 9 and connected with the spring member 5 shown in FIG. 2. The first shaft 8 and second shaft 9 have a flanged cylindrical shape, and cylindrical parts are fitted into the corresponding boss parts 35 and 36 on the side of the frame from the corresponding first arc-shaped groove 20 and second arc-shaped groove 21. That is, in this operation, the arm 3 is placed such that each boss part 35 and 36 is overlaid on the corresponding first arc-shaped groove 20 and second arc-shaped groove 21 from one side of the frame 2.

The first shaft 8 and second shaft 9 are fixed to the corresponding boss parts 35 or 36 through the first arc-shaped groove 20 and second arc-shaped groove 21 from the other side of the frame 2, and each screw 38 is fixed in the small-diameter attachment holes 35 a and 36 a through the cylinders of the first shaft 8 and second shaft 9. Also, after the arm 3 is installed on the frame 2, the spring member 5 is placed between the arm 3 and the frame 2, whereby the apparatus 1 of the embodiment becomes a unit product. The spring member 5 is a coil member and the like, as shown in FIG. 2. One end of the spring member 5 is fixed over the engaging part 29 on the side of the frame, and the other end thereof is fixed over the engaging part 37 on the side of the arm.

(Example of installation on a device) The apparatus 1 described above is commercially available and handled as a unit product, in which the frame 2 is installed on the main body 10, and the arm 3 is connected to the cover 15. In this case, the frame 2 is fixed at multiple places with screws 18 or the like, while the attachment piece 24 and the attachment pieces 27 and 28 are placed at the corresponding attachment parts 14 c to 14 e on the lower surface 14 of the main body (refer to FIG. 2 and FIG. 3). After the projection 15 a on the side of the cover is fitted into the insertion hole 31 a of the connecting part 31, the arm 3 is connected to the cover 15 by a screw 19 or the like inserted from the attachment hole 31 b. Of course, the attachment structure also may be a different one, and is designed appropriately in accordance with the shapes and the like of the main body 10 of the device and the cover 15.

(Operation) Next, an operation of the apparatus 1, or a cover opening and closing mechanism, will be explained with reference to FIGS. 1(a) to 1(c), 4(a) and 4(b), and 6. In FIGS. 4(a) and 4(b), and 6, for clearly explaining a relationship between the teeth parts 23 a to 23 d on the frame side and the damper 6, i.e. the damping means, the damper 6 and the rotating gear 7 are indicated by hidden lines. Also, in FIGS. 5(a) and 5(b), the cover is omitted due to limitation of the drawing space.

(1) FIG. 4(a) is the closed state of the cover 15. In this closed state, the lower part of the arm 3 is positioned inside the escape groove 14 b of the main body 10. Also, the first shaft 8 is positioned at one end 20 a of the first arc-shaped groove 20, and the second shaft 9 is positioned at the other end 21 b of the second arc-shaped groove 21. Also, the cover 15 is held in a state covering the front surface 11 of the main body 15 by the force of the spring member 5. On the other hand, FIG. 4(b) is the open (fully open) state of the cover 15. In this open state, the lower part of the arm 3 is inserted greatly in the escape groove 14 b. Also, the first shaft 8 is positioned at the other end 20 b of the first arc-shaped groove 20, and the second shaft 9 is positioned at the one end 21 a of the second arc-shaped groove 21. Also, the cover 15 is held in a state that the cover 15 moves to the lower side of the main body 15 by the force of the spring member 5 and the part projecting forward is small. Accordingly, in the apparatus 1, or the cover opening and closing mechanism, with the forcing means working during the opening and closing operation of the cover 15, it is possible to eliminate locking means in the conventional apparatus, thereby reducing cost and improving the external appearance characteristics.

(2) FIGS. 5(a) and 5(b) show a state in the middle of the opening and closing operation in which the cover 15 is rotated by fixed angles from the closed state to the open state, respectively. FIG. 5(a) is the state when the cover 15 is rotated from the closed state in the open direction against the force of the spring member 5, and the first shaft 8 slides from the one end 20 a of the first arc-shaped groove 20 toward the side of the other end 20 b with the second shaft 9 as a fulcrum. In this state, the spring member 5 is extended up to the maximum length and the force is increased. Also, from this state, the cover 15 is automatically rotated to the open state shown in FIG. 4(b) from the state shown in FIG. 5(b) by the spring member 5 with the force spring-charged. That is, when an operator releases the cover 15 (edge or recessed part 15 b or the like) in the state shown in FIG. 5(a), the second shaft 9 slides from the other end 21 b of the second arc-shaped groove 21 to the side of the one end 21 a with the first shaft 8 at the other end 20 b as a fulcrum, and the cover 15 is rotated and switched to the open state shown in FIG. 4(b).

The cover 15 is switched from the open state to the closed state through a reverse operation of the operation described above. That is, the operator rotates the cover 15 against the force of the spring member 5 from the closed state to midway between the open state and closed state as shown in FIG. 5(a), and releases the cover 15. Accordingly, the cover 15 is switched to the closed state by the force of the spring member 5. Thus, with the apparatus 1, or the cover opening and closing mechanism, it is operated against the force of the spring member 5 only in the initial stage when the cover 15 is rotated from the closed state to open state or from the open state to closed state. The cover 15 is automatically rotated and switched respectively by the spring member 5 in mid course, thereby improving the operability of switching as compared with the conventional apparatus.

(3) In the apparatus 1, since the rotating gear 7 of the damper 6 on the side of the arm engages one of the teeth parts 23 a to 23 d provided at multiple places on the side of the frame, the cover 15 is always damped throughout the entire process of rotating and switching between the closed state and open state in the above manner. This is realized by constructions as follows. In the first construction, for example, the rotating gear 7 engages the lower teeth part 23 b (23 d) in the closed state shown in FIG. 4(a). Then, during the opening and closing operation shown in FIGS. 5(a) and 5(b), and in the open state shown in FIG. 4(b), the rotating gear 7 engages with the upper teeth part 23 a (23 c). That is, the rotating gear 7 engages the upper teeth part 23 a (23 c) and the lower teeth part 23 b (23 d) in a switching manner.

In the second construction, the numbers of teeth of the upper and lower teeth parts 23 a and 23 b on the side of the left frame 2 are different from those of the upper and lower teeth parts 23 c and 23 d on the side of the right frame. For example, the rotating gear 7 of the damper 6 on the side of the left frame 2 rotates idly during switching of the engagement from the lower teeth part 23 b shown in FIG. 4(a) to the upper teeth part 23 a shown in FIG. 5(a). During that idle rotation, the rotating gear 7 of the damper 6 on the side of the right frame 2 maintains the engagement with one of the upper and lower teeth parts 23 c and 23 d. Accordingly, with the apparatus 1, or the cover opening and closing mechanism, even when the dual-shaft construction is adopted and the rotational track of the cover 15 is made complex, the damping force is applied in the entire process of rotation, thereby improving quality.

(4) In the apparatus 1, as shown in FIGS. 4(b), 5(a) and 5(b), the cover member 4 automatically rotates when the cover 15 is switched from the closed state to the open state. Also, the cover part 41 stands up in front of the escape groove 14 b of the main body 1. That is, the cover member 4 is rotated downwardly by the force of the coil spring 17 with the attachment shaft 26 as a fulcrum accompanying the rotation of the arm 3 in the open direction. Also, the stopper piece 42 contacts the restriction piece 25 to be held in the usage mode, that is, the upright state.

Also, the cover member 4 is rotated upwardly accompanying the rotation of the arm 3 toward the close direction while the cover part 41 is pushed up by the arm 3 against the force of the coil spring 17, and is received inside the main body 10 while increasing a tilt from the escape groove 14 b. Accordingly, with the apparatus 1, even though the escape groove 14 b is added for providing the rotational track of the arm 3 to move from the front surface of the main body 10 to beneath the lower surface, because the front side of the escape groove 14 b is covered with the cover part 41 of the cover member 4 in the open state of the cover 15, the external appearance characteristics are maintained.

As described above, according to the present invention, the constituent members are simple as compared with the conventional dual-shaft construction. Also, it is possible to improve the characteristics of rotation and switching of the cover 15, and to apply to a wide range of devices, thereby expanding applications.

The disclosure of Japanese Patent Application No. 2003-352396, filed on Oct. 10, 2003, is incorporated in the application.

While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims. 

1. A cover opening and closing mechanism for opening and closing a cover relative to a corresponding part of a main body, comprising: a guide groove section provided on the main body and including a first arc-shaped groove with two ends and a second arc-shaped groove with two ends arranged with a distance in between, a shaft section provided on the cover for slidably situated in the guide groove section and including a first shaft guided in the first arc-shaped groove and a second shaft guided in the second arc-shaped groove, and forcing means provided between the main body and the cover for urging and holding the cover in a closed state such that the first shaft is positioned at one of the two ends of the first arc-shaped groove and the second shaft is positioned at one of the two ends of the second arc-shaped groove, said cover switching from the closed state to an open state such that the second shaft slides toward the other of the-two ends of the second arc-shaped groove around the first shaft after the first shaft slides toward the other of the two ends of the first arc-shaped groove around the second shaft.
 2. A cover opening and closing apparatus according to claim 1, wherein said forcing means is an expandable spring and arranged such that in opening the cover, when the first shaft reaches the other of the two ends of the first arc-shape groove from the closed state to expand the spring, the cover is opened automatically by the spring.
 3. A cover opening and closing apparatus for opening and closing a cover relative to a corresponding part of a main body, comprising: an upright wall provided on the main body and including a first arc-shaped groove with two ends and a second arc-shaped groove with two ends arranged with a distance in between, an arm provided on the cover and including a first shaft slidably guided in the first arc-shaped groove and a second shaft slidably guided in the second arc-shaped groove, and forcing means provided between the upright wall and the arm for urging and holding the cover in a closed state such that the first shaft is positioned at one of the two ends of the first arc-shaped groove and the second shaft is positioned at one of the two ends of the second arc-shaped groove, said cover switching from the closed state to an open state such that the second shaft slides toward the other of the two ends of the second arc-shaped groove around the first shaft after the first shaft slides toward the other of the two ends of the first arc-shaped groove around the second shaft.
 4. A cover opening and closing apparatus according to claim 3, further comprising damping means provided between the upright wall and the arm for damping a rotational speed of the cover.
 5. A cover opening and closing apparatus according to claim 4, wherein said damping means includes a damper with a rotating gear attached to the arm, and a plurality of teeth parts provided at different positions on the upright wall so that the rotating gear engages the teeth parts in a switching manner from one of the teeth parts to the other of the teeth parts.
 6. A cover opening and closing apparatus according to claim 3, further comprising an escape groove formed in a front bottom wall of the main body for escaping the arm, and a cover member pivotally supported on the upright wall for standing up to cover the escape groove when the cover switches from the closed state to the open state. 